CRT vs LCD is orthogonal to the question I've posed here. Only after the incoming signal is converted to RGB do the differences between LCD and CRT matter.

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Is this 'trick' exclusive to the PAL region?

In practice, it's exclusive to PAL. PAL specifies color recovery by using a delay line of precise length and using the additive and subtractive interference between the current and delayed color signals, while NTSC specifies color recovery by using a PLL to demodulate QAM and different bandwidths for the orange-vs-blue and green-vs-purple axes.

A few modern NTSC sets add a comb filter to attempt to exchange some vertical color resolution in exchange for horizontal, but the results are harder to predict, vary more from set to set, and may sometimes be disabled for sufficiently non-standards-compliant inputs (such as from a NES). TVs that use a "3d" comb filter would be ludicrously difficult to drive in a predictive fashion, especially given the NES's limited palette.

How would this look on a CRT? Given the NES was designed to be played on a CRT, it seems like a fitting question to ask.

The results are (mostly) the same on my CRT. There are some rare color combinations that the CRT and HDTV don't seem to agree on, IIRC one of them produced a greyish tone on my HDTV, but some actual color on my CRT. Probably a detail of how the filter is implemented.

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Does anybody have a good idea how the chroma merging could be simulated in AviSynth? I guess it should be something like 1) convert to YUV (or YCbCr, strictly speaking) 2) separate the Y, U and V planes 3) scale the U and V planes by 0.5, and blend them with a shifted version of themselves 4) combine back to YUV.

Does anybody have a good idea how the chroma merging could be simulated in AviSynth? I guess it should be something like 1) convert to YUV (or YCbCr, strictly speaking) 2) separate the Y, U and V planes 3) scale the U and V planes by 0.5, and blend them with a shifted version of themselves 4) combine back to YUV.

Using the frames from the video you'd posted, I did the following in gimp:- Rescale nearest-neighbor down to 288 scanlines high- Colors / Components / Decompose / YCbCr ITU R470- Select the Cb layer; Filters / Generic / Convolution Matrix / the matrix that looks like

I'd also tried using a diagonal delay (the NES's scanline is too long), but I didn't really notice an appreciable difference. I guess any difference probably requires that it operate on the modulated chroma signal, not the baseband components.

Not sure if related, but I noticed that when playing Batman on PAL NES (CRT TV), in the very beginning of level 2-1 parts of the background graphics changed colors as the screen scrolled vertically (when jumping up to the platforms with wall jump, and coming down again).

Has anybody else from PAL land noticed the same happening with Batman?

I didn't notice that with Batman, but I clearly remembering seeing that in Kid Icarus. It changed so much I was sure the game wrote to the colour emphasis bits, before verifying in an emulator that actually it doesn't.

You could get around it if you only scrolled vertically in increments of 2. That'd fix background flashing, but sprites would still have the same issue unless you locked their (display) Y position to increments of 2 as well. I don't think this would have a HUGE effect on gameplay.

I didn't notice that with Batman, but I clearly remembering seeing that in Kid Icarus. It changed so much I was sure the game wrote to the colour emphasis bits, before verifying in an emulator that actually it doesn't.

Yeah I tested Kid Icarus now as well, and it's very noticeable there right from the beginning.

Noah's Ark is a PAL game that uses blue emphasis combined with the grayscale bit to flood the level with water. I can't really remember if I tried that game in NTSC mode/consoles, but I've certainly never seen the water being any other color.

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